The correct answer is B) A solution might become obsolete over time.
The sentence that best explains why politicians continually need to reevaluate domestic policy is "A solution might become obsolete over time."
When politicians made a decision about domestic policy or design a solution for a specific problem, it only applies to that specific problem during a certain period. Issues change over time and politicians need to be permanently reviewing the policies because problems change and people's necessities also change. So innovation and prevention are two key factors when creating domestic policies.